JPS58222179A - Cathode ray tube for display - Google Patents

Abstract

PURPOSE:To provide the titled cathode ray tube with a high degree of resolution, prepared by forming on a face plate a fluorescent film consisting mainly of an orange fluophor with a long afterglow which contains zinc cadmium sulfide as a matrix, a specified activator and 1st and 2nd coactivators. CONSTITUTION:The cathode ray tube for monochromatic display is prepared by providing an electron gun which has a beam diameter of 0.05-0.4mm. on a fluorescent surface and emits a cathode ray with a frame frequency of 20-50Hz and forming a fluorescent film consisting mainly of an orange fluophor with a long afterglow on a face plate opposing the electron gun. The fluophor contains zinc cadmium sulfide of the formula (where 0.15<=x<=0.35) as a matrix, copper or gold as an activator, Ga or I as 1st coactivator and one of Ci, Br, I, F and Al as 2nd coactivator. The activator and 1st and 2nd coactivators are used in 10<-4>-1wt%, 10<-6>-10<-1>wt% and 5X10<-6>-5X10<-1>wt%, respectively, of the matrix.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube, and more particularly to a cathode ray tube for monochrome displays having a high brightness, long afterglow, orange-emitting fluorescent film.

In recent years, high-resolution display cathode ray tubes have been desired to be used in computer terminal display devices, aircraft control system display devices, etc. that display minute characters and graphics.

The phosphor film of such a cathode ray tube for high-resolution displays needs to be composed of a phosphor with long afterglow properties. this is,
When the phosphor film of a cathode ray tube is composed of a short afterglow phosphor,
This is because flickering occurs on the screen due to the slow scanning speed of the fluorescent film. In general, the phosphor that makes up the phosphor film of such high-resolution display cathode ray tubes has an afterglow time (in this specification, the time required for the luminance to drop to 10% of the excitation level after excitation is stopped). In other words, it is necessary that the "10% afterglow time" is several tens to hundreds of times longer than that of the short afterglow phosphor that constitutes the phosphor film of an ordinary cathode ray tube.

In particular, cathode ray tubes (orange-emitting high-resolution monochrome displays)
Cathode ray tubes (hereinafter abbreviated as cathode ray tubes) are widely used in these applications because they cause less visual fatigue even when viewed for long periods of time.

Conventional practical long-afterglow orange-emitting phosphors used in such cathode ray tubes include a green-emitting manganese-activated zinc silicate phosphor (P39 phosphor) and a red-emitting manganese-activated phosphor. A mixed phosphor of zinc fluorescein (P27 fluorescer) was used. However, since this phosphor is a mixture of phosphors of two completely different emission colors, color unevenness occurs when the resolution is increased, making it unsuitable for practical use and lacking in sufficient brightness. In addition, a lead- and manganese-activated calcium silicate phosphor (P25 phosphor) is known as a single phosphor that emits orange light with a long afterglow, but its luminance is extremely low and is not practical. Furthermore, since the color of the emitted light hardly changes depending on the amount of activation, etc., it was not possible to exhibit the various emitted colors required of a cathode ray tube.

On the other hand, in recent years, there has been a demand for cathode ray tubes that can be adapted to a wide variety of uses.
Furthermore, it has been desired to develop a cathode ray tube whose phosphor film is an orange-emitting phosphor with long afterglow that emits high-intensity light.

Furthermore, compared to conventional color television cathode ray tubes, high-resolution cathode ray tubes are required to have significantly higher phosphor uniformity due to their functions. In both cases, the particle shape and particle size distribution are unfavorable for coating purposes, resulting in extremely low yields in the production of cathode ray tubes, which is a serious industrial disadvantage.

An object of the present invention is to provide a cathode ray tube whose phosphor film is an orange-emitting phosphor that has a long afterglow property and can select any emission color from orange close to red to orange close to yellow.

Another object of the present invention is to provide a cathode ray tube whose phosphor film is a long-afterglow orange-emitting phosphor that emits high-intensity light.

Still another object of the present invention is to provide an orange-emitting cathode ray tube having a uniform and high-yield phosphor film.

The cathode ray tube of the present invention has a beam diameter of 0.05 to 0.05 on the fluorescent surface. 4 mra
It is equipped with an electron gun that emits cathode rays with a frame frequency of 20 to 50 Hz, and the compositional formula (Zrr+-x, Cd
x) S (where X is a number satisfying the range 0.15≦X≦035) zinc cadmium sulfide is used as the base material, at least one of copper or gold is used as the activator, and at least one of gallium or indium is used as the first a coactivator, at least one of chlorine, bromine, iodine, fluorine, and aluminum is used as a second coactivator, and the activator, the first coactivator, and the second coactivator It is characterized in that the amount of the agent is 10 -4 to 1% by weight and 10 -6 to 10 -1% by weight, respectively, with respect to the matrix.

The phosphor film of the cathode ray tube of the present invention may be formed only from the above-mentioned long-afterglow orange-emitting phosphor, or may be formed from a small amount of other materials in order to adjust the emission color or afterglow time. It may also be formed from a mixture of phosphors.

The sulfide phosphor used in the cathode ray tube of the present invention has a parent C
By selecting the amount of d, the type of activator, and the amount of activation, any luminescent color from orange close to red to orange close to yellow can be obtained, and the coating properties are also good and the brightness is high. Therefore, when the cathode ray tube of the present invention is combined with the electron gun,
A cathode ray tube was obtained which has a luminescent color suitable for display use and excellent image quality (resolution, uniformity, etc.).

The sulfide phosphor used in the present invention is a sulfide phosphor having the same matrix, using either copper or copper and gold as an activator and the second co-activator as a co-activator. The afterglow time after excitation by electron beams, ultraviolet rays, etc. is stopped is several tens to hundreds of times longer than that of fluorescent materials.

Note that the afterglow time values stated in this yPIh document are based on the assumption that the current density of the stimulating electron beam emitted from the electron gun is 0.4.
μA/c/! This is the value when .

The phosphor used in the present invention has a long afterglow time (changes depending on the current density of the stimulating electron beam), which is a characteristic that conventional long afterglow phosphors do not have. The smaller the light, the longer the afterglow time will be.

The present invention will be explained in detail below.

As shown in FIG. 1, the structure of the cathode ray tube of the present invention is almost the same as that of a conventional monochromatic cathode ray tube such as a cathode ray tube for black and white television, except for the electron gun, firefly, and light film components. . That is, in the cathode ray tube of the present invention, the neck portion 2 of the funnel 1
An electron gun 3 is provided at the top, and a fluorescent film 5 is formed on the entire surface of a face plate 4 facing the electron gun 3. Generally, an aluminum vapor deposited film 6 is provided on the back surface of the fluorescent film 5 to prevent charge-up during excitation. The cathode ray tube constructed in this manner is characterized by comprising a phosphor film 5 made of a phosphor that emits green to yellowish green light with a specific long afterglow, and an electron gun 3 having a specific beam diameter and frame frequency.

Regarding the manufacturing method of the long-afterglow orange-emitting phosphor used in the present invention, the present applicant has previously filed a patent application filed in 1986-25.
Please refer to No. 545 for a detailed explanation.

The long-afterglow orange-emitting phosphor used in the present invention, obtained based on the manufacturing method described in the above-mentioned Japanese Patent Application No. 57-25545, etc., has a compositional formula of (Zr++-x, Cdx)S.
(However, X is a number satisfying the range 015≦X≦035) Zinc cadmium sulfide is used as the base material, at least one of copper or gold is used as the activator, and at least one of gallium or indium is used as the first co-added material. an activator, at least one of chlorine, bromine, iodine, fluorine and aluminum as a second co-activator; A phosphor in an amount of 10-4 to 1% by weight, 10-6 to 10-1% by weight and 5X10-6 to 5X10'% by weight, respectively, based on the matrix against 10'%8X10
% by weight of sulfur. ). The amounts of the above-mentioned activator, first co-activator and second co-activator are each 10-3 to 6X in terms of image quality and brightness of the cathode ray tube.
More preferably 10-'wt%, 5X10'' to 5X10''wt% and 5X10-5 to 10-1wt%.

The emission color of this phosphor varies from orange close to red to orange close to yellow depending on the amount of cadmium, the type of activator, and the amount of activation.

When the amount of cadmium is increased, a longer wavelength emission color is exhibited, and generally when the amount of copper and gold, which are activators, is increased, a longer wavelength emission color is exhibited. Further, the afterglow characteristics (afterglow time, etc.) are mainly determined by the selected type and activation amount of the first co-activator and the selected type and activation amount of the second co-activator. Further, the electron gun used in the present invention emits cathode rays having a beam diameter of 0.05 to 0.4 mm at the fluorescent surface and a frame frequency of 20 to 50 Hz.

FIGS. 2 and 3 illustrate the emission spectra of the phosphor used in the cathode ray tube of the present invention. Figure 2 shows the emission spectrum of the phosphor used in the cathode ray tube of the present invention, which uses gold as an activator, and has a compositional formula of (Zno, 5zcd).
o, +s) S: Au, Ga, A, d (however,
Au = 1.4 x 10'wt%, Ga = 5
X], 0''% by weight, A7 = 6 x 10% by weight). This is the emission spectrum of the phosphor used in the cathode ray tube of the present invention, and the composition formula is (Zno, 7scdo, 22) S
:'Cu, Ga, Al (However, CI=1.2X
10”wt%, Ga=-1,5×10wt%, A)-
It is 3×10% by weight. ) is the emission spectrum of the orange-emitting hexagonal phosphor.

As shown in FIGS. 2 and 3, the phosphor used in the present invention exhibits good orange light emission.

FIG. 4 is a graph illustrating the afterglow characteristics of the phosphor used in the cathode ray tube of the present invention. In FIG. 4, the curve has a compositional formula (Z, no, 5zCdo, +s)S: Au,
Ga, kl (However, Au=1.4 x 10
'wt%, Ga=5XIO-'wt%, Al=6x
10% by weight. ) is the afterglow characteristic of the orange-emitting phosphor after electron beam excitation is stopped.

As is clear from FIG. 4, the phosphor used in the present invention exhibits an afterglow time of approximately 30 milliseconds, which is sufficient for use in displays.

FIG. 5 shows the emission color of the cathode ray tube of the present invention (a diagram representing the chromaticity points of the JE color system. Point A is (Zno, 52Cdo; +s
) S is the base material, and the amounts of Au, Ga, and Al activators are 1.4X10'wt% and 5X, respectively, relative to the base body.
With phosphors that are 10-3 wt.% and 6X10'' wt.%, point B is (,Zn,o,7scdo,2
2) S is the parent body, Cu, Ga.

5 From the figure, it can be seen that the orange-emitting phosphor of the present invention shows good orange color development with a single phosphor.Therefore, the mixed phosphor of P27 phosphor and P39 phosphor has a long afterglow property. Unlike the case where orange light emission is produced, in the long afterglow orange light emitting phosphor of the present invention, color unevenness in the emitted light color does not occur.

Further, since the phosphor used in the present invention has a matrix of zinc sulfide, the particle size can be easily obtained from several microns to more than ten microns depending on the manufacturing method. In addition, conventional long-afterglow orange-emitting phosphors have unfavorable particle shapes and particle size distributions, making it difficult to obtain a good fluorescent film, but the fluorescent film used in the present invention has an almost spherical shape. Therefore, a good fluorescent film can be obtained.

As described above, the cathode ray tube of the present invention can provide a good orange luminescent color. Further, since the phosphor used itself emits light with high brightness and can form a good fluorescent film, it is possible to obtain light with higher brightness than in conventional cathode ray tubes.

Incidentally, a small amount of a conventionally known phosphor may be mixed with the phosphor used in the present invention to adjust the emission color and afterglow characteristics.

Further, in the phosphor used in the present invention, a part of the first coactivator may be substituted with scandium. Further, the phosphor of the present invention may be further activated with an activator such as divalent europium, bismuth, or antimony. Furthermore, in the phosphor of the present invention, part of the sulfur may be replaced with selenium in order to shift the emission wavelength to a slightly longer wavelength side.

Additionally, pigments can be attached to or mixed with the phosphors used in the present invention to improve the contrast of the phosphors. Pigments that have an orange color that is almost the same as the luminescent color of the phosphor (lead, molybdenum orange, cadmium selenide sulfate, etc.) and black pigments (iron oxide, tungsten, etc.) are used as the pigments to be attached. is used in an amount of 0.5 to 40 parts by weight per 100 parts by weight of the phosphor of the present invention.

The sulfide phosphor of the present invention can be subjected to any of the surface treatments and particle size selections used for conventionally known sulfide phosphors.

As described above, the cathode ray tube of the present invention exhibits high-intensity orange light emission due to a good fluorescent surface, and has extremely high industrial utility value.

Next, the present invention will be explained by examples.

Example l ZnS 750 g CdS 25oI f(AuC14-4H20, 2,93,9Ga(NO3
)3-8l-1z0 0.287 gA12(SO4
)3.18f-1z0 7.40F After thoroughly mixing these phosphor raw materials using a ball mill, appropriate amounts of sulfur and carbon were added and the mixture was charged into a quartz crucible. After the quartz crucible was covered, the crucible was placed in an electric furnace and fired at a temperature of 950° C. for 3 hours. During this firing, the inside of the crucible was in a carbon disulfide atmosphere. The fired product obtained after firing was taken out from the crucible, washed with water, dried, and passed through a sieve.

In this way, the activation amounts of gold, gallium, and aluminum are each 1.4X10' of the zinc sulfide cadmium matrix.
wt%, 5X10'' wt% and 6X10'' wt%
(Zno, 5zCdo, 1s) S: Au,
A Ga, Al phosphor was obtained.

This phosphor had a median particle size distribution of 8 microns, and was a particle exhibiting a spherical morphology with a sharp particle size distribution.

Using this fluorophore, apply 4 mI onto the face plate using the sedimentation method.
I/CI? A fluorescent film was formed by coating the film in an amount of L. This fluorescent film was smooth and good. Using this and an electron gun whose beam diameter was set to 0.2 mm and whose frame frequency was set to 4.0 Hz, the cathode ray tube of the present invention shown in FIG. 1 was obtained.

The emission spectrum of this cathode ray tube is shown in FIG. 2, and its afterglow time was about 30 milliseconds as shown in FIG. 4, and a good display was obtained. The color of the emitted light is given by point A in Figure 5 (X=0.56. Y=0.4
3).

This cathode ray tube has approximately twice the brightness compared to a conventional cathode ray tube using a mixed phosphor consisting of a P27 phosphor and a P39 phosphor.

Example 2 ZnS 700g Cd5 300.9 CLISO4・51-120 0.4.72 gG
a(NO3)a -81-1200,086,! i'A
72(SO4)a -181-1203,709 Using these phosphor raw materials, the activation amounts of copper, gallium, and aluminum were determined in the same manner as in Example 1. 2X10 wt%, 1,5X1
．． O wt% and 3X10-2 wt% (Z, n
o, 7scdo, 2z) S: Cu, Ga, Al phosphors were obtained. This phosphor had a medium value of particle size distribution of 9 microns, and was a particle exhibiting a spherical morphology with a sharp particle size distribution. Using this phosphor, 5m9/Cr! A fluorescent film was formed by applying the solution in several directions. This fluorescent film was smooth and good. In addition to this, the beam diameter is 0.3 mm and the Freno frequency is 4.
587. The cathode ray tube of the present invention shown in FIG. 1 was obtained by using the electron gun set as shown in FIG.

This cathode ray tube had an afterglow time of about 20 milliseconds after the electron beam excitation stopped, and a good display was obtained. The color of the emitted light is at point B in Figure 5 (x=0.56. Y=0.
44).

This cathode ray tube has approximately twice the brightness compared to a conventional cathode ray tube using a mixed phosphor consisting of a P27 phosphor and a P39 phosphor.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the cathode ray tube of the present invention, FIGS. 2 and 3 are emission spectra of the phosphor used in the cathode ray tube of the present invention, and FIG. 4 is a sectional view of the phosphor used in the cathode ray tube of the present invention. FIG. 5 is a graph illustrating the afterglow characteristics of the body. FIG. 5 is a CIE color system color change degree dot diagram showing the emission color of the cathode ray tube of the present invention. Tophanel 2... Neck part 3... X-ray M4... Face spray 1, 5... Firefly film
6. Aluminum vapor deposited film 19- Figure 5 Related Patent Applicant Address: 2-7-18 Hamamatsucho, Minato-ku, Tokyo Name:
Kasei Optonics Co., Ltd. 4, Agent 5-2-1-6 Roppongi, Minato-ku, Tokyo Number of inventions increased by amendment None 7
Insert the following sentence between lines 10 and 11 of page 8 of the description of the contents of the amendment in column 8 of "Detailed explanation of one invention to be amended" in the specification.

Claims (4)

[Claims] (1) Beam diameter at fluorescent surface is 0.05 to 0.4 m
m, equipped with an electron gun that emits cathode rays with a frame frequency of 20 to 5 Q Hz, and a composition formula (Zn+-x, Cd
x) S (where X is a number that satisfies the range of 0.15≦X≦035) with zinc cadmium sulfide as the base material, an activator of at least one of copper or gold, and at least one of gallium or indium as the first a co-activator, a small amount of salt, bromine, iodine, fluorine and aluminum (one of which is a second co-activator, the said activator, the first co-activator and the second co-activator) 1. A cathode ray tube for a monochrome display, characterized in that the amount of co-activator is applied to the matrix to form a phosphor film whose main component is a phosphor by weight of 10<-4 >1. (2) The cathode ray tube for monochrome display according to claim 1, wherein the electron gun has a beam diameter of 0.07 to 0.3 mm and a frame frequency of 25 to 40 Hz. (3) The activation amount of the activator, the first co-activator, and the second co-activator is 10-3 to 6 x 10% by weight, respectively, 5
×10~5×10″″′wt% and 5×10~10
3. A cathode ray tube for monochrome display according to claim 1 or 2, characterized in that the amount is % by weight. (4) The fluorescent film contains a pigment having an orange or black body color in an amount of 05 to 40% by weight based on the long afterglow orange-emitting phosphor. A cathode ray tube for monochrome display according to any one of item 3.